Ontogenetic development of the helical heart: concepts and facts

Abstract

The structural and functional organization of the ventricular myocardial mass is a controversial matter that cannot be resolved by anatomical studies alone. Therefore, other approaches such as investigations of the ontogenetic development of the ventricular myocardium might help to resolve controversies about its structural and functional organization. It has recently been proposed that the spatial orientation of Torrent-Guasp's ventricular myocardial band model (basal and apical loops) might be the mature morphological correlate of twists and torsions of the embryonic heart loop. In the present contribution, the suggestions made in this concept were analyzed in the light of currently known facts about the development of the embryonic heart. It was found that some of the suggestions made in this concept do not correspond to embryological facts, whereas other suggestions could neither be disproved nor confirmed on the basis of our current knowledge on heart development. The answer to the question as to which of the various models of myocardial fibre organization fits best with the ontogenesis of the myocardial mass awaits future studies. The myocardial units of Torrent-Guasp's myocardial band model are said to have a functional rather than a morphological personality. Future studies on the ontogenetic development of the myocardium, therefore, should comprise not only anatomical analyses of dead specimens but should additionally comprise high resolution in vivo analyses of the development of the spatio-temporal contraction patterns of embryonic and fetal hearts.

Barium-enhanced imaging of the coronary vasculature of the porcine myocardium: empirical investigation into the theory of the ventricular myocardial band

“…In addition to anatomical analyses of dead specimens, analyses of ontogenetic development of the VMB and coronary vessels and their interactions are necessary for future evaluation of the relations between the VMB and coronary blood systems. 13 The results of this study should be applied to human hearts because the similarities of the coronary artery anatomy between swine and humans Short-axis view of the VMB wrapped into a double helical coil and coronary blood supply. The ventricular wall consists of two layers of muscle band, but in the posterolateral wall the ventricular wall actually become a single layer owing to a crossover point have been pointed out.…”

Insights from echocardiography, magnetic resonance imaging, and microcomputed tomography relative to the mid‐myocardial left ventricular echogenic zone

“…Support for the concept of the myocardial band is also lacking from studies investigating the development of the embryonic cardiac loop . Neither does data from ventricular activation support the notion of a myocardial band.…”

“…Support for the concept of the myocardial band is also lacking from studies investigating the development of the embryonic cardiac loop. 37,38 Neither does data from ventricular activation support the notion of a myocardial band. The propagation of electrical waves within the ventricles normally originates in the endocardium near the apical septum and proceeds from endocardium to the epicardium and toward the base.…”

The anatomy of cardiac looping: A step towards the understanding of the morphogenesis of several forms of congenital cardiac malformations

“…Concomitantly with the rapid elongation of the heart tube, its dorsal mesocardium disappears between its venous and arterial poles and its configuration changes from that of a straight tube into that of a helically wound loop (Bremer, 1928;Grant, 1964;Mohun et al, 2000;Männer, 2004Männer, , 2006b. Helical tubes are asymmetric structures that principally can occur in two mirror-imaged variants, one displaying clockwise and the other displaying counterclockwise winding.…”